Dry development of silylated resist has been studied using an O-2 plasma generated by a multipolar electron cyclotron resonance source. Etch rate, uniformity selectivity, and profile were investigated as a function of process parameters including microwave power, RF power, now rate, sample area, pressure, temperature, and gas addition. It was found that etch rate increases as microwave and/or RF power increase. Vertical etch profile was obtained by using low pressure (3 mTorr) and 50 W RF power. As the area of the samples was increased from 1 to 81 cm(2), the etch rate decreased from 0.85 to 0.6 mu m/min at a now of 10 sccm O-2 but remained constant at 0.9 mu m/min with 100 sccm O-2. Etch rate was independent of temperature and decreased with the addition of N-2 or CF4. Etch uniformity was within +/-3% across a 150 mm wafer for most etch conditions. The selectivity of the silylated layer over the photoresist degraded from 445 to 14 as RF power was increased from 25 to 100 W. Residue-free surface and vertical profile have been obtained with features as small as 0.1 mu m